package <%= packageName %>.security;

import <%= packageName %>.service.JwtService;
import jakarta.servlet.FilterChain;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.RequiredArgsConstructor;
import org.springframework.lang.NonNull;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;

import java.io.IOException;

@Component
@RequiredArgsConstructor
public class JwtAuthFilter extends OncePerRequestFilter {

    private final JwtService jwtService;
    private final UserDetailsService userDetailsService;

    @Override
    protected void doFilterInternal(
            @NonNull HttpServletRequest request,
            @NonNull HttpServletResponse response,
            @NonNull FilterChain filterChain
    ) throws ServletException, IOException {
        final String authHeader = request.getHeader("Authorization");
        final String jwt;
        final String userEmail;

        if (authHeader == null || !authHeader.startsWith("Bearer ")) {
            filterChain.doFilter(request, response);
            return;
        }

        jwt = authHeader.substring(7);
        try {
            userEmail = jwtService.extractUsername(jwt);

            if (userEmail != null && SecurityContextHolder.getContext().getAuthentication() == null) {
                UserDetails userDetails = this.userDetailsService.loadUserByUsername(userEmail);

                if (jwtService.isTokenValid(jwt, userDetails)) {
                    UsernamePasswordAuthenticationToken authToken = new UsernamePasswordAuthenticationToken(
                            userDetails,
                            null,
                            userDetails.getAuthorities()
                    );
                    authToken.setDetails(
                            new WebAuthenticationDetailsSource().buildDetails(request)
                    );
                    SecurityContextHolder.getContext().setAuthentication(authToken);
                }
            }
        } catch (Exception e) {
            // Token is invalid, expired, or has a mismatched signature.
            // We do not throw here so that permitAll endpoints (like /login and /register)
            // can still be accessed even if the browser sends a stale token.
        }
        
        filterChain.doFilter(request, response);
    }
}